Artículo
Cellular origin of the Bufo arenarum sperm receptor gp75, a ZP2 family member: Its proteolysis after fertilization
Fecha de publicación:
04/2008
Editorial:
Portland Press
Revista:
Biology Of The Cell
ISSN:
0248-4900
Idioma:
Inglés
Tipo de recurso:
Artículo publicado
Clasificación temática:
Resumen
Background information. The egg envelope is an extracellular matrix that surrounds oocytes. In frogs and mammals, a prominent feature of envelope modification following fertilization is the N-terminal proteolysis of the envelope glycoproteins, ZPA [ZP (zona pellucida) A]. It was proposed that ZPA N-terminal proteolysis leads to a conformational change in egg envelope glycoproteins, resulting in the prevention of polyspermy. Bufo arenarum VE (vitelline envelope) is made up of at least four glycoproteins: gp120 (glycoprotein 120), gp75, gp4l and gp38. The aim of the present study was to identify and characterize the baZPA (B. arenarum ZPA homologue). Also, our aim was to evaluate its integrity and functional significance during fertilization. Results. VE components were labelled with FITC in order to study their sperm-binding capacity. The assay showed that gp75, gp4l and gp38 possess sperm-binding activity. We obtained a full-length cDNA of 2062 bp containing one ORF (open reading frame) with a sequence for 687 amino acids. The predicted amino acid sequence had close similarity to that of mammalian ZPA. This result indicates that gp75 is the baZPA. Antibodies raised against an N-terminal sequence recognized baZPA and inhibited sperm-baZPA extracted from VE binding. This protein does not induce the acrosome reaction in homologue sperm. Northern-blot studies indicated that the transcript is exclusively expressed in the ovary. In situ hybridization studies confirmed this and pointed to previtellogenic oocytes and follicle cells surrounding the oocyte as the source of the transcript. baZPA was cleaved during fertilization and the N-terminal peptide fragment remained disulfide bonded to the glycoprotein moiety following proteolysis. Conclusion. From the sequence analysis, it was possible to consider that gp75 is the baZPA. It is expressed by previtellogenic oocytes and follicle cells. Also, it can be considered as a sperm receptor that undergoes N-terminal proteolysis during fertilization. The N-terminal peptide could be necessary for sperm binding.
Archivos asociados
Licencia
Identificadores
Colecciones
Articulos(CEFYBO)
Articulos de CENTRO DE ESTUDIOS FARMACOLOGICOS Y BOTANICOS
Articulos de CENTRO DE ESTUDIOS FARMACOLOGICOS Y BOTANICOS
Articulos(CICYTTP)
Articulos de CENTRO DE INV.CIENT.Y TRANSFERENCIA TEC A LA PROD
Articulos de CENTRO DE INV.CIENT.Y TRANSFERENCIA TEC A LA PROD
Citación
Scarpeci, Sonia Laura; Sánchez, Mercedes Leonor; Cabada, Marcelo Oscar; Cellular origin of the Bufo arenarum sperm receptor gp75, a ZP2 family member: Its proteolysis after fertilization; Portland Press; Biology Of The Cell; 100; 4; 4-2008; 219-230
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